Sewing machine for producing superposes stitches



April 4, 1939. 1.. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 25, 1957 10Sheets-Shet 1 INVE OR I I T %RNEY April 4, 1939.

' L. ROSEMAN.

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 25, 1957 10Sheets-Sheet 2 lfllllilf 2 Z INVENTOR y BY XATTORNEY April 4, 1939.ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPER1?OSED STITCHES Filed Jan. 25, 1937 10Sheets-Sheet s lNVENT E '1 AT RNEY April 4, 1 939. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1937lO-Sheets-Sheet 4 ORNEY April 4, 1939. -L. ROSEMAN 2,153,006

' SEWING MACHINE FQR PRODUCING suPERPosED STITCHES Filed Jan. 23, 193710 Sheets-Sheet 5 NVENTOR TORNEY p l 1939- L.. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHBS Filed Jan. 23, 1937lOSheets-Sheet 6 ORNEY April 4, 1939. L. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 10SheetsSheet 2 VENTQR April 4,- '1939. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SQPERPOSED STiTCHES Filed Jan..23, 193vIO-Sheets-Sheet s 2' QVENTOR I BY M I April 4, 1939. ROSEMAN' 2,153,005

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 10Sheets-Sheet 9 2 IQENTOR BY M QRNEY April 4, 1939. L, R$EM N 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 1OSheets-Sheet l0 fix) lgZVENTOR I A ORNEY Patented Apr. 4, 1939 UNITEDSTATES PATENT OFFICE- SEWING MACHINE FOR PRODUCING SUPERPOSED STITOHESLeo Roseman, Newark, N. J.

Application January 23, 1937, Serial No. 121,993

4 Claims.

This invention relates in general to a sewing machine having the needlebar movable back and forth in a plane parallel to the direction of movelrection of feed of the work or transversely of the work or zig-zagstitches, and also for forming jump or skip stitches between twoadjacent series of superposed stitches, whereby the operations may beperformed rapidly and automatically and 15 the formation of the stitchesshall be extremely accurate.

A further'object is to provide such a machine.

whereby the length of running stitches canbe increased or decreasedautomatically by control 20 of said back and forth movement of theneedle in conjunction with work feed mechanism.

The invention is especially useful in forming gaps between two pieces ofmaterial to receive fastener elements, with superposed stitches at the25 ends of the gaps for reenforcing the work at those points and topermit the fasteners to be brought close to the edges of the pieces ofmaterial, for example as shown in my copending applications Serial No.744,642 filed September 19, 1934, and

30 Serial No. 106,326 filed October 19, 1936. Also, the invention iscontemplated for use in making tying stitches for securing snapfasteners on tape, for example as shown in my copending applicationSerial No. 92,711 filed July 27, 1936, where 35 the fastener elementshave apertures and lines of stitches run longitudinally of the tape andseries of superposed or tying stitches pass through said apertures andthe tape in traversing relation to the fastener elements. 40 In knownmachines for making superposed tying stitches running in the directionof the work feed, for example as shown in my said application Serial No.744,642 or in my Patent No. 2,052,896 dated September 1, 1936, the feedof the work 45 is periodically reversed, or the work is movedalternately manually or automatically in opposite ,Other prime objectsof the present invention are to provide a novel and improved method ofand machine for forming superposed stitches running in'the direction ofnormal feed of the work and without the necessity of reversing the 5work feed or reciprocating the work; and thus to provide such a methodand machine wherein the needle shall both reciprocate to pierce andwithdraw from the work and move back and forth or oscillate in a planeparallel with the direction of feed of the work, and the reciprocationand back andforth movement of the needle shall be correlated'fwith themovement of the work feed mechanism to form superposed stitches.

Another object is to provide such a method and machine wherein the workshall be fed continuously step-by-step in the usual way, and the backand forth movement oroscillation of the needle shall be controlled toform superposed stitches during and without interruption or variation inthe feeding of the work.

Further objects are to provide a method and machine of the generalcharacter described including the reciprocatory needle that is alsomovable back and forth, wherein the length of the stitches may be variedby control of the back and forth movement of the needle without changein the work feed; and also to provide a method and machine wherein thefeed of the work shall be varied or interrupted during back and forthmovement or oscillation of the needle to form the superposed stitches.

Another object is to provide a method and machine of the characterdescribed whereby jump stitches may be formed by back and forth movementof the needle in conjunction with normal feed of the work, withoutincreasing or diminishing the length of a step of feed, and withoutpreventing formation of a stitch.

A further object is to provide in such a machine novel and improvedautomatic means for controlling back and forth movement of the needle,and novel and improved automatic means for controlling feed of the work,both of which shall be simple, reliable and relatively inexpensive.

Other objects are to provide a method and machine of this characterwhereby a continuous line of stitches may be formed having spaced seriesof superposed stitches extending in the direction tain other results andadvantages as will be brought out by the following description whenread'in conjunction with the accompanying drawdifferent steps in theoperation of the machine.

Figures 4A and 5A are schematic plan views of a portion of the workshowing the operations performed by the machine with the parts inpositions shown in the respective Figures 4 and 5. Figure 6 is an endelevation of a modified form of the machine with the cover plate. of thestitching head removed.

Figure 7 is an end elevation of the stitching head.

Figure 8 is a front elevation of the form of the machine shown in Figure6.

Figure 9 is a vertical sectional view through the stitching head withthe needle bar supporting bracket removed.

Figure 9A is a detached perspective view of a needle bar.

Figure 10 is a bottom plan view of a machine showing the feed drivingmechanism.

Figure 11 is a plan view ofthe cam for oscilating the needle bar shownin Figures 6 to 10 inclusive.

Figure 12 is a fragmentary development cam surface shown in Figure 11.

Figure 13 is a view similar toFigure 11 showing the cam for controllingoscillation of the needle bar in the form of the invention shown inFigures 1 to 5 inclusive.

Figure 14 is a similar view of another modification of the cam foroscillating the needle.

Figure 15 is a plan view of the cam forconof the trolling operation ofthe work feed mechanism shown in Figures 1 to 5 inclusive.

Figure 16 is a plan view of the work feed cam corresponding to themodified needle oscillating cam shown in Figure 14.

Figure 17 is a composite schematic view showing the various steps ofoperationv of the machine shown in Figures 1 to, 5 inclusive.

Figure 18 is a similar view showing of operation of the machine shown inFigures 6 to 10 inclusive.

Figure 19 is a similar view showing the steps of operation of the othermodified machine embodying the cams shown in Figures 14 and 16.

Figures 20 to 39 inclusive are schematic end elevations of the stitchforming mechanism and work showing the functions of the oscillatingneedle in the form of the machine shown in Figures 1 to 5 inclusive.

Figures 40 to 59 are similar views showing the functions of theoscillatingneedle in the form of the invention shown in Figures 6 to 9inclusive,

and

Figures 60 to 79 inclusive are like views showing the functions of theoscillating'needle in the modified form of machine embodying the camsillustrated in Figures 14 and 16. v

Specifically describing the embodiment of the invention illustrated inFigures 1 to 5 inclusive the reference character A designates the bedplate of the machine which has the usual standard B thereon, formed witha goose neck C at a bobbin mechanism 0 of the steps one end of which ismounted the stitching head D. In the stitching head is a needle bar Ewhich is mounted to move back and forth in a plane parallel to thedirection of movement of the work. As shown (see Fig. 6), the needle baris reciprocatory in a bracket F which is pivotallymounted at G to .swingabout a horizontal axis, and the needle bar carries one or two needlesH, as desired, which are caused to penetrate and withdraw from the workupon reciprocation of the needle bar in known manner. The needle bar maybe driven in the usual way from the drive shaft I of the machine whichis joumaled in the standard B and goose neck C, and as shown, the shaftI carries a disk K on which is a wrist pin L which is connected by alink M to a pin N on the needle bar. 7

With the needle bar and its needles cooperates the usual type, theneedle bar, its operating devices and the bobbin and its cooperatingparts, constituting a stitch anism for moving work through the stitchforming mechanism, that is, between the needles and the bobbins, and asshown, this work feed mechanism includes the usual presser foot PP and afeed dog P which is movable vertically and horizontally relatively tothe usual throat plate 2 in the bed of the machine, the dog being raisedthrough the throat plate Q and moved horizontally in one direction inengagement with the work to move the latter and then being lowered awayfrom the work and being moved horizontally in the other direction to itsinit al position. The dog is operated from the driv shaft I of themachine and as shown is mounted on a link B. one end of which isbifurcated at S to embrace a cam T on a counter-shaft U joumaled in thebed plate of the machine. The other end of the link It is pivotallyconnected at V to a crank W on another countershaft X journaled in thebed of the machine. The counter-shaft U is rotated by a belt and pulleyconnection Y from the drive as shown in my copending application SerialNo. 744,642-filed September 19, 1934. As shown, the

counter-shaft X has a pin I projecting laterally therefrom through aslot 2 in the bed plate of the machine, the end of the pin beingarranged in an opening 3 in an actuating slide 4 so that the pin has ahinged or pivotal connection with the slide and reciprocation of theslide will cause rotation of the shaft alternately in oppositedirections. The slide is mounted on the bed of the machine in suitableguides 5.

One end of the slide 4 has a pin and slot connection 6 with one end of aIever'l which is pivotally mounted at 8 on a horizontal axis'on'abracket 9 secured on the top of the bed A of the machine. A followerroller I0 is joumaled on an arm H on the lever I and cooperates with acam AA, being held in engagement with the cam by a spring l2, so thatthe cam oscillates the lever 1 to cause reciprocation of the slide 4,0scillation of the shaft X and reciprocating horizontal movement of thefeed dog P. The form of the cam AA will be varied to correspond to thelength, character and spacing oithe stitches to be produced ashereinafter described so as to move the work in one directionstep-by-step and periodically momentarily interrupt movement of thework.

For oscillating or moving the needle bar back and forth in timedrelation to the movement of the work feed mechanism and reciprocation ofthe needle bar, I have shown the bracket F (see Figures 4, 5 and 6)provided with a lateral pin l3 which is connected to a link I4 slidablymounted by a bolt and slot connection I5 in the stitching head D. Theend of the link projects beyond the rear side of the stitching head andhas a pin and slot connection IS with one end of a lever H which ispivotally mounted intermediate its ends at It? on a standard I!) securedto w the top of the bed A of the machine. The other cams.

end of the lever ll carries a follower roller 20 which follows a cam BBand is held in engagement with the cam by a tension spring 2!. The formof the cam BB will be varied to correspond to the length and timing ofthe oscillating movements desired in the needle bar, as hereinafterdescribed, so as to move the needle bar back and forth in a planeparallel to the direction of movement of work by the work feedmechanism.

As shown, both cams AA and BB are mounted on an auxiliary shaft 22 thatis journaled with its axis vertical in bearings 23 and. 24, and has aworm gear 25 which meshes with a worm 26 on the drive shaft 1.Preferably the ratio of the gearing 25, 26 is such that the cam will bero-- As shown, the machine so far described is adapted to form lines ofstitches running longitudinally of the work and including spaced seriesof superposed stitches 217, and jump stitches 28 and running singlestitches 29 between the series of superposed stitches (see Figures 17and 20 to 39), Accordingly the work feed cam. AA shown in detail inFigure 15 includes a plurality of cam surfaces 30 and 3| andcorresponding dwells 30A and MA. When the follower roller l0 moves fromone of the dwells 3lA upon one of the cam surfaces 30 the feed dog P isreciprocated in the direction to feed the work to the left of Figure 3,

the cam T having previously raised the feed dog from the position shownin Figure 3 through the throat plate into engagement with the work; andas the roller it) leaves each dwell 30A at d passes over the cam surface3| onto the dwell 3IA the feed dog is. moved in the opposite direction,the cam T'havi'ng previously lowered the feed dog away from the work.The cam also has two concentric dwells 32 for interrupting movement ofthe work during the formation of the two series of superposedstitches'at each end of each jump stitch 28, and between the dwells 32are cam surfaces 33 and 34 and corresponding dwells 33A and 34A forfeeding the work a distance equal to two stitches for formation of thejump stitch 28. The number of the surfaces 30 and 3! will be dependentupon the number of running stitches 29 to be made between the series ofsuperposed stitches 21.

The corresponding needle bar oscillating cam BB has a plurality of camsurfaces 340 each corresponding -to one of the cam surfaces 30 0f thecam AA, for controlling the needle bar during the formation of-therunning stitches 29 there being dwells 34! between the cam surfaces 340.

At one end of the series of cam surfaces 340 is a cam surface 35 andcorresponding dwell 35A for permitting movement of the needle bar underthe influence of the spring 2| in the direction corresponding to thedirection of movement of the work for formation of one of the superposedstitches 2'! at one end of the jump stitch 28; and adjoining the dwell35A is another cam surface 36 and corresponding dwell 36A for moving theneedle bar in the other direction for forming another superposed stitchof said series. Adjacent the dwell 36A is a cam surface 31 andcorresponding dwell 31A for moving the needle bar in the directionopposite the direction of movement of the work for forming the jumpstitch, and adjacent the dwell 31A are the cam surfaces 38 and 39 andcorresponding dwells 38A and 39A for moving the needle bar to form twoof the superposed stitches atthe other end of the jump stitch.

In the operation of the machine, assuming that the machine is at thepoint of beginning the formation of the first series of superposedstitches 2?; the needle bar is in its central or neutral position afterformation of the first stitch2lA of the series of superposed stitches,as shown in Figure 20, with the needle withdrawn from the work. At thispoint the feed mechanism follower roller I0 is in engagement with one ofthe dwells 32 ,of the cam AA so that the feed dog P is stationary andout of contact with the work as shown in Figure 3. The cams rotate inthe direction of the arrows of Figures 13 and 15, and the needle baractuating roller 22 then is engaged by the cam surface 35 so as to swingthe needle bar backwardly or in the direction of the normal feed of thework, a distance equal to the length of one stitch as shown in Figure21, whereupon the needle is caused by the drive shaft I and link M topenetrate the work to complete the second superposed stitch ZlB as shownin Figure 22. Thereupon the roller 20 is engaged by the cam surface 36which swings the needle bar forwardly the same distance whereupon the,needle again penetrates the work to form the third superposed stitch210 as shown in Figure 25." The needle bar is then withdrawn from thework and is in its neutral or initial position and continued movement ofthe cams causes engagement of the cam surface 31 with the roller 20' soas to swing the needle bar forwardly or in a direction opposite that ofmovement of-the work a distance equal to the length of one stitch or onestep of feeding movement of the feed dog. Simultaneously with theswinging of the needle, the feed dog is actuated to move the workforwardly one step by one cam surface 33 of the cam AA as shown inFigure 27. The needle is then caused to penetrate and withdraw from thework as shown in Figures 28 and 29 to complete the jump stitch 28',equal in length to two normal stitches. Thereupon the work is advancedone step by the other cam surface 33 and the needle penetrates andwithdraws from the work to form the first stitch 211) of the otherseries of superposed stitches at the end of the jump stitch 28 as shownin Figures 30 to 32. Then the movement/of the work feed mechanism isinterrupted by the cam dwell 32 and the needle bar is swung rearwardlyin the direction of normal feed of the work by cam surface 38 andpenetrates and withdraws from the work to form the second stitch 21E asshown in Figures 33 to 35 inclusive, while held by dwell 38A againstoscillation, after which the needle bar is swung by the cam projection39 in the direction opposite to normal feed of the work and penetratesand withdraws from the work to form the last superposed stitch 27F asshownin Figures 36 to 38 while held by dwell 99A against oscillation.Then operation of the work feed mechanism is resumed, the cam surfaces30 and 3! and their dwells 99A and MA being successively brought intoengagement with the roller l0 and the cam surfaces 340 and dwells 3being successively brought into engagement with' the roller 29 so as toform a series of running stitches 29.

It is necessary that the needle bar be returned from the position shownin Figure 38 to its initial or neutral position shown in Figure 20 bythe time the work has reached the point for formation of the next seriesof superposed stitches. For this purpose the needle oscillating cam BBhas the cam projections 340 progressively eccentric to the axis ofrotation of the cam so as to move the needle bar step-by-stepsynchronously with the movement of the work feed mechanism in thedirection of work feed, each step of a length corresponding to thedistance of movement of the needle bar in the direction of movementof'the work during the formation of the second superposed stitch, i. e.the length of one step of movement of the work feed mechanism, dividedby the number of running stitches 29 between the series of superposedstitches.

The various steps in the formation of the stitches and the nature of thestitches is also illustratedin Figure 1'7, the formation of the firstthree superposed stitches while the work is stationary and the needle isoscillated being shown at l'IA-|'IC, the formation of the skip stitchwhile the work is advanced and the needle is moved in the directionopposite to movement of the work being shown at D, the formation of thenext superposed stitches being shown at |7C-l'IG and the beginning offormation of the running stitches with the work advancing being shown at"H and "I. 1

Itwill beobserved from the foregoing that reciprocation and back andforth movement of the needle and movement of the work feed mechanism arecorrelated and operate in corresponding cycles to form during each cyclea series of running stitches 29, in the present instance 76 stitches,followed by a series of three superposedstitches 27 followed by a jumpstitch 28 which is in turn followed by another series of threesuperposed stitches 21. The cam surfaces and,

dwells of the two cams AA and BB are of such size and so related to eachother and to the needle reciprocating mechanism that the work is fedstep-by-step, the needle penetrates and withdraws the work while thework is stationary between its steps of movement, and the needle isoscillated while it is out of the work.

A modification of the invention is shown in Figures 14, 16 and to '79inclusive whereby the return of the needle bar to its neutral positionafter the formation of the superposed stitches as above described isobviated. In this form of .the invention the needle bar oscillatesbetween two limits and assumes only two difierent positions; and theneedle is always located the same distance at one side or the other ofthe central point between the two limits of movement.

The work feed cam and needle oscillating cam for this form of theinvention are shown in Figures 16 and 14 respectively. The work feed camCC has a series of cam. surfaces-l0 and 4| and corresponding dwells 40Aand A for forming the running stitches, while the needle actu- VIII isin engagement with the dwell 46 ofthe cam CC and on continued movementof the cams, the roller 20 rides over the cam surface 47 to move theneedle one step in the direction of movement of the work as shown inFigure 61, after which the roller 20 rides on the, dwell 48. The needlethen penetrates and withdraws from the work as shown in Figures 62 and63 and the work feed follower roller I0 is engaged by a cam surface 49which moves the work one step as shown in Figure 64. While the roller ison the dwell 50 the needle penetrates and withdraws from the work asshown in Figures and 66 to form the third superposed stitch. Thereuponthe work feed roller I0 is engaged successively by the cam surfaces 5|and 52 to move the work two steps forwardly, and the needle oscillatingroller 20 is engaged by the cam surface 53 to swing the needle one stepin the direction opposite to that of movement of the work as shown inFigure 67. The roller III is then on the dwell 54 and the roller 20 ison the dwell 55, and the needle penetrates and withdraws from the workas shown in Figures 68 and 69 to form the skip stitch. The needle bar isstill held against oscillation by the dwell 55 while the work isadvanced one step by the cam surface 58. While the roller I0 is on thedwell 59 the needle penetrates and withdraws from the work as shown inFigures '71 and '72 to form the first superposed stitch. The needle isthen swung in the direction of movement of the work one step by the camsurface 56, as shown in Figure '73, and the needle penetrates andwithdraws from. the work to form the second superposed stitch as shownin Figures '74 and-75. Thereupon the work is moved one step in advanceby the cam surface GI and simultaneously the needle is swung one step inthe direction opposite to that of movement of the work by the camsurface 62 as shown in Figure '76. The needle then penetrates andwithdraws from the work to form the third superposed stitch. It will beobserved that the needle is now in its initial position as shown inFigure 60 and ready to begin the formation of the next series of runningstitches, the roller 26 being on the concentric dwell 42 of cam DD andthe roller I0 engaging the cam surfaces 40 and 4| to move the workstep-by-step to form the running stitches, the first of which is shownin Figure '79.

In Figure 19 the formation and nature of the stitches as above described'is schematically illus-- trated, the formation of the first superposedstitch before the jump stitch being shown at 79A and the formation ofthe second secondary stitch being shown at 19B, both while the work issta-- movement of the work or two in the work is fed continuously stepby step by the usual work feeding mechanism of the sewing machine. Thestitch forming mechanism is the same as that hereinbefore described andthe mechanism including the feed dog and the parts R, S, T and U formoving it toward and from the work, are the same as hereinbeforedescribed. The feed dog is reciprocated back and forth by the usual"mechanism including the shaft EE which corresponds to the shaft X abovedescribed and which is oscillated by the usual crank and pitmanconnection FF from the drive shaft I of the machine, instead of by theslide 4' and pin 1 of the form of the machine shown in Figures 1 and 3.The link R which carries the feed dog is pivotally connected to an armGG on the shaft EE just as said link R is connected to the crank W onthe shaft X.

The cam for oscillating the needle is designated HI-l'and is shown indetail in Figures 11 and 12. The cam includes a series of cam surfaces65 and corresponding dwells 66 which are similar to the cam surfaces anddwells 340 and 34! above described, for forming the running stitches. Inthis form of the invention the needle is mounted to swing a distanceequal to the length of two steps of movement of the work feed mechanism,and at the end of the first superposed stitch before the jump stitch,the needle is in its foremost position toward the front of the machineas shown in Figure 40. Inthis position the follower roller 26 is aboutto be engaged by the cam surface t'l upon rotation ofthe cam HH in thedirection of the arrow, and as the roller rides over this cam surface,the needle is swung two steps in the direction of movement of the workas shownin Figure 41. It will be remembered that the work iscontinuously moving and will have moved one step simultaneously with theabove mentioned movement of the needle, so that the needle will be inposition to penetrate the work atthe beginning of the first superposedstitch as shown in Figure 41. The roller 26 will then ride over thedwell 68 while the needle penetrates and withdraws from the work to formthe second superposed stitch as shown in Figures 42 and 43. The workwill then move another step, whereupon the needle will again penetrateand withdraw from the work to form the third superposed stitch as shownin'Figures 45 and 46. Thereupon the roller 20 will ride over the camsurface it whereby the needle will be swung in a direction opposite tothat of movement of the work a distance equal to two steps of movementof the work or two stitches, and simultaneously the work will moveforwardly one step, as shown in Figure 47. Thereupon the roller 20 willengage the dwell H and the needle will penetrate and withdraw from thework as shown in Figures 48 and 49 so as to form a jump stitch equal inlength to three normal stitches. The roller 20 will continue on thedwell ll while the work goes forwardly another step as shown in Figure50, whereupon the needle will penetrate and withdraw from the work toform the first superposed stitch at the end of the jump stitch as shownin Figures 51 and 52. Then the roller 20 will ride over the cam surface12 so- 1 that the needle is swung in the direction of movement of thework a distance equal to two steps of stitches, and the work will moveforward one step as shown in Figure 53. The needle will then pene-'trate and withdraw from the work to form the.

second superposed stitch as shown in Figures 54 ment of the roller withthe cam surface 65 and I dwells 66 to complete the series of runningstitches.

It is necessary, by the time the first superposed stitch of the nextseries is to be formed, thatthe needle be returned to its initialposition shown in Figure 40, and accordingly the cam surfaces 65 anddwells 65 are progressively eccentric to the axis of rotation of the camHH in a manner similar to that of the cam surfaces 340 and 3 of the camBB. Accordingly the needle will be moved in the direction opposite tothat of movement of the work in equal steps each of a length equal tothe distance of movement of the needle from one limit of oscillation tothe other, divided by the number of running stitches between the seriesof superposed stitches. i

In Figure 18 is shown schematically the formation and nature of thestitches, the formation of the first superposed stitch corresponding toFigure 40 being shown at IBA, the formation of the second and, thirdsuperposed stitches preceding the jump stitch being shown at MB and MC,

and the formation of the jump stitch being shown at MD. The formation ofthe next series of superposed stitches is shown at l8E to [8G inclusive,while the formation of the first two running stitches after thesuperposed stitches at the end of the jump stitch is shown at "SH andI81.

It will be understood by those skilled in the art that the number ofsuperposed stitches may be varied and the length of the jump stitchesmay also be varied, and the number of running stitches may be varied, bysimply modifying the number and shape of the various cam surfaces anddwells of the cams and changing the timed relation of the oscillation ofthe needle bar, the movement of the work feed mechanism and thereciprocation of the needle. As will be apparent from the foregoing, byvarying the shapes and relation of the cam surfaces and the cam dwells,the length of running stitches can be increased or decreasedautomatically, and continuously if desired, by back and forth movementof the needle and without change in the work feed. Also, should it bedesired to make more superposed stitches than is possible with the rangeof oscillation of the needle, the mechanism might be modified to stopfeed of the work momentarily and produce more oscillations of theneedle.

Where it is impractical to use the feed dog work feed mechanism abovedescribed, for example in stitching snap fasteners on tape, I may usefeed rollers such as shown in my Patent No. 2,052,896 for feeding thework.

The use of the back and forth movement of the needle to vary the lengthof the stitches or form superposed stitches ensures extremely accurateand rapid stitching, as compared with use i of the work feed mechanismfor reversing or varying the feed of the work where time is lost bymanipulation of the feed mechanism and accuracy is affected by lostmotion between the many parts and between the feed dog and the work.

It is highly desirable, especially in making fastener tape, that thejump stitches and superposed stitches be accurately spaced, and theusual feed dog work feed mechanism above described sometimes permitsrelative slipping of the work and the work feed dog and between whichthe work to be operated upon is gripped, one roller being mounted in theframe of the machine ona shaft 83 and the other mounted on a shaft 84 ina frame 85 pivoted at 86 so that the roller 8| may be influenced towardthe roller 80 by a spring 81. The rollers are geared together to rotateat the same peripheral speeds by meshing pinions 82, one on each of therollershafts 83 and 84, and one of the shafts, in the present instancethe shaft 83, is driven by a helical gear connection 88 with a jackshaft 89 which has a helical gear connection 90 with the counter-shaft22. The rollers 8|] and 8| more firmly grip the work than do the presserfoot and feed dog, and feed the work accurately in timed relation to thestitch form-' ing mechanism. The feed dog is normally adjusted to feed alength of work slightly greater than the length supplied by the feedrollers for each stitch to ensure that the full amount of work shall bebrought to. the needle, and the pressure of the feed dog on the work issuch that it may slip beneath the work afteryit has fed the exact amountcontrolled by the feed rollers. With this construction, the work ispositively gripped between the feed rollers 80 and 8| and the rollersare constantly rotated at a uniform speed in timed relation to the driveshaft and the needle, so that the work may be fed with accuracy and thejump stitches 28 may be accurately spaced in the work and over-feed ofthe work is prevented. Under feed also is prevented by the adjustment ofthe dog feed to feed more than desired and the preventing of excess feedby'the rollers 80, 8| which hold back the work to the feed desired, thedog slipping slightly over the work to compensate therefor. 1

Where it is desired that 'two sets of stitches shall be made and exactlyspaced to enter apertures in an object on the'work, or shall be madewith one tightly against each of opposite/sides of an object on thework, for example ..a fastener element, as shown respectively in mydependin application's Serial No. 92,711, filed July-27, 1 and SerialNo. 106,326, filed October 19, 1936, the present invention utilizing twoneedles is especially useful, because the needles can be accuratelyspaced one at each side of the fastener element and the two sets ofstitches can be formed automatically and simultaneously. Should the twosets of stitches be made at different times with a single needle, thetime required would be at least doubled, and it would be practicallyimpossible to cause the stitches to tightly hug opposite sides of thefastener elements in an automatic operation, and without stopping of themachine and possible manual manipulation of the work, because orpossibility of movement of the fastener element between the operationsor change in relation of the work to the needle dur-. ing the formationof the second set of stitches.

Other modifications in the method and structure of the machine willoccur to those skilled in tliie art as within the spirit and scope ofthe invent on.

Having thus described my inventiomwhat I claim is:-

1. In a sewing machine, the combination of work feed mechanism, stitchforming mechanism including a reciprocatory needle that is also movableback and forth in a plane parallel with the direction of movement of thework, automatic means for moving the work feed mechanism continuously inone direction step-by-step with one step for each reciprocation of theneedle, means for continuously reciprocating the needle in timedrelation to step-by-step movement of the work feed mechanism to formrunning stitches, and automatic means operative during reciprocation ofthe needlefor moving said needle back and forth while it is out of thework and to suecessively move the needle in the direction of movement ofthe work simultaneously with a step of movement of the work a distanceequal to a multiple of the length of said step of movementof the workand hold the needle against back or forth movement during the next stepof movement of the work, to form a series of superposed stitches.

2. In a sewing machine, the combination of work feed mechanism, stitchforming mechanism including a reciprocatory needle that is also movableback and forth in a plane parallel with the direction of movement of thework, .automatic means for moving the work feed mechanism continuouslyin one direction step-by-step with one step for each reciprocation .ofthe needle, means for continuously reciprocating the needle in timedrelation to step-by-step movement of the work feed mechanism to formrunning stitches, and automatic means operative during reciprocation ofthe needle for moving said needle while it is out of the work and in thedirection opposite to movement of the work simultaneously with a step ofmovement of the work.

3. In a sewing machine, the combination of work feed mechanism, stitchforming mechanism including a reciprocating needle that is also movableback and forth in a plane parallel to the direction of movement of thework, automatic means for controlling the work feed mechanism in cyclesin timed relation to reciprocation of said needle' to form a stitch uponeach reciprocation of the needle, and automatic means operative duringreciprocation of the needle for moving said needle back and forth whileit is out of the work at different intervals and diflerent distances ineach cycle of movement of the work feed mechanism and in timed relation.to reciprocation of the needle.

4. In a sewing machine, the combination of work feed mechanism forfeeding work step-bystep, stitch forming mechanism including a needlethat is reciprocable and is also movable in a plane parallel to thedirection of movement of the work, means for reciprocating said needle.to form a stitch of given length upon each step of movement of the work,and automatic means operative during reciprocation of the needle formoving said needle in said plane'while the needle is out of thework andin steps synchronous with the movement of the work andeach of a lengthless than the corresponding step of movement of the work to vary thelengths of the stitches.

